Pentacon six lens and lens adapter The Pentacon Six mount (commonly abbreviated to P6, or Б in Cyrillic) is a breech-lock bayonet lens mount originally used by several medium format single-lens reflex cameras from East Germany. The lens mount was originally designed by Carl Zeiss Jena and Kamera Werkstätten (KW) for the Praktisix camera. KW later merged with several other companies to become VEB P